Technical Abstract:
The EPA clean air act sets specific levels of acceptability for particulate matter (PM) in the air, at PM 2.5 microns that level is .065 mg/m*3. Objectives of this study were to measure dust levels and microbiological contaminants on dust from pig units. A wheat field and a building at Texas Tech University were controls. Treatment sites were an indoor and outdoor gestation unit, and an indoor and outdoor farrowing unit. Dust was measure for two 24 hr periods at each site using dust meters (Dust Trak, TSI, MN). Bacterial and fungal counts were determined by taking 5 min samples with a six-stage Anderson Sampler (Anderson, GA). Plates containing media favorable to either bacterial or fungal growth were incubated 48 hr and colonies were counted. The experiment was a repeated measure design. Dust levels were higher (P<.001) on d 2 except in the indoor farrowing unit. Dust levels at the gestation units also increased (P<.001) on d 2 but were similar (P>.05) between indoor and outdoor units (mean indoor .006 vs .049 and outdoor .004 vs .052, SE=.0007, mg/m*3 for d 1 & 2). The outdoor farrowing pasture had a higher (P<.001) number of fungal colonies compared to all other environments (mean=122.6, SE=6.19 total counts). Most fungi were at stages 3 through 6 corresponding to PM between 3.3 and .65 microns. Total bacterial counts did not differ (P>.05) among environments. The outdoor farrowing pastures had the lowest dust levels for both days. Fungi are known allergens and have potential to be carried into the respiratory tract of animals dust particles, especially at PM 4 microns or less. Our results indicate that methods of reducing particulate matter on certain days are needed in west Texas to enhance animal health and wellbeing within indoor and outdoor pig production units.